Broad Antiviral Effects of Echinacea purpurea against SARS-CoV-2 Variants of Concern and Potential Mechanism of Action

Critical analysis of Echinacea preparations marketed in Germany

Colds are the most common cause of incapacity to work in 2023 and therefore have a significant impact on the German economy. Echinacea preparations are considered a non-specific immune stimulant that is used as a phytotherapeutic agent for the treatment and prevention of colds. In the 2021 ZEIT ranking of the best-selling pharmacy-only medicines in Germany, four Echinacea preparations were among the top ten, and they experienced a new hype during the SARS-CoV-2 pandemic. In this study, 22 Echinacea monopreparations, which are approved as herbal medicinal products, were analyzed based on their package inserts. The preparations used in clinical studies were compared with the preparations available on the market with regard to the criteria of plant species used, plant part used, preparation (extract or pressed juice), drug-extract ratio, single dose administered, standardization of the preparations, prior performance of an ingredient analysis, galenics, dosage, duration of administration, and daily dose administered. The analysis revealed that the preparations available on the market are very heterogeneous. The composition can vary considerably in terms of ingredients. For customers, these products appear homogeneous in terms of their presentation on the market. The legal framework conditions promote this situation. The clinical studies are also unable to adequately reflect the market situation. New studies based on market reality, with an analysis of ingredients in the preparations used, a standardized study design, and the inclusion of hematological and biochemical parameters in the evaluation should improve this situation. Days of incapacity for work as an outcome parameter could be well suited.

Phytochemistry, Mechanisms, and Preclinical Studies of Echinacea Extracts in Modulating Immune Responses to Bacterial and Viral Infections: A Comprehensive Review

BACKGROUND

Echinacea species, particularly Echinacea purpurea, Echinacea angustifolia, and Echinacea pallida, are renowned for their immunomodulatory, antibacterial, and antiviral properties.

OBJECTIVES

This review explores the mechanisms by which echinacea herbal extracts modulate immune responses, focusing on their effects on both innate and adaptive immunity in bacterial and viral infections.

RESULTS

Key bioactive compounds, such as alkamides, caffeic acid derivatives, flavonoids, and polysaccharides, contribute to these effects. These compounds enhance immune cell activity, including macrophages and natural killer cells, stimulating cytokine production and phagocytosis. The antibacterial activity of echinacea against respiratory pathogens (Streptococcus pneumoniae, Haemophilus influenzae, Legionella pneumophila) and skin pathogens (Staphylococcus aureus, Propionibacterium acnes) is reviewed, as well as its antiviral efficacy against viruses like herpes simplex, influenza, and rhinovirus. Echinacea's potential as a complementary treatment alongside conventional antibiotics and antivirals is discussed, particularly in the context of antibiotic resistance and emerging viral threats.

CONCLUSIONS

Challenges associated with variability in phytochemical content and the need for standardized extraction processes are also addressed. This review provides a comprehensive overview of echinacea's therapeutic potential and outlines future directions for research, including clinical trials and dosage optimization.

Anatolian medicinal plants as potential antiviral agents: bridging traditional knowledge and modern science in the fight against COVID-19 and related viral infections

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was the cause of the coronavirus 2019 (COVID-19), commonly known as the coronavirus pandemic. Since December 2020, COVID-19 vaccines have been extensively administered in numerous countries. In addition to new antiviral medications, the treatment regimen encompasses symptom management. Despite sustained research efforts, the outbreak remains uncontrolled, with affected patients still lacking proper treatment. This review is a valuable asset for researchers and practitioners aiming to delve into the yet unexplored potential of Anatolian flora in the fight against COVID-19 and other viral infections. Numerous medicinal plants in Anatolia, such as thyme, sage, cannabis, oregano, licorice root, and Origanum sp., contain bioactive compounds with proven antiviral properties that have been used in the region for centuries. The rich legacy of traditional Anatolian medicine (TAM), has significantly influenced modern medicine; thus, the profusion of medicinal plants native to Anatolia holds promise for antiviral drug development, making this review essential for researchers and practitioners.

Immunomodulatory Effect of Phytoactive Compounds on Human Health: A Narrative Review Integrated with Bioinformatics Approach

BACKGROUND

Immunomodulation is the modification of immune responses to control disease progression. While the synthetic immunomodulators have proven efficacy, they are coupled with toxicity and other adverse effects, and hence, the efforts were to identify natural phytochemicals with immunomodulatory potential.

OBJECTIVE

To understand the immunomodulatory properties of various phytochemicals and investigate them in Echinacea species extracts using an in silico approach.

METHODOLOGY

Several scientific database repositories were searched using different keywords: "Phytochemicals," "Alkaloids," "Polyphenols," "Flavonoids," "Lectins," "Glycosides," "Tannins," "Terpenoids," "Sterols," "Immunomodulators," and "Human Immune System" without any language restriction. Additionally, the study specifically investigated the immunomodulatory properties of Echinacea species extracts using gene expression analysis of GSE12259 from NCBI-GEO through the Bioconductor package GEOquery and limma.

RESULTS

A total of 182 studies were comprehensively analyzed to understand immunomodulatory phytochemicals. The in silico analysis highlighted key biological processes (positive regulation of cytokine production, response to tumor necrosis factor) and molecular functions (cytokine receptor binding, receptor-ligand activity, and cytokine activity) among Echinacea species extracts contributing to immune responses. Further, it also indicated the association of various metabolic pathways, i.e., pathways in cancer, cytokine-cytokine receptor interaction, NF-kappa B, PI3K-Akt, TNF, MAPK, and NOD-like receptor signaling pathways, with immune responses. The study revealed various hub targets, including CCL20, CCL4, GCH1, SLC7A11, SOD2, EPB41L3, TNFAIP6, GCLM, EGR1, and FOS.

CONCLUSION

The present study presents a cumulative picture of phytochemicals with therapeutic benefits. Additionally, the study also reported a few novel genes and pathways in Echinacea extracts by re-analyzing GSE 12259 indicating its anti-inflammatory, anti-viral, and immunomodulatory properties.

ECHOPvir: A Mixture of Echinacea and Hop Extracts Endowed with Cytoprotective, Immunomodulatory and Antiviral Properties

Respiratory viral infections continue to pose significant challenges, particularly for more susceptible and immunocompromised individuals. Nutraceutical strategies have been proposed as promising strategies to mitigate their impact and improve public health. In the present study, we developed a mixture of two hydroalcoholic extracts from the aerial parts of Echinacea purpurea (L.) Moench (ECP) and the cones of Humulus lupulus L. (HOP) that can be harnessed in the prevention and treatment of viral respiratory diseases. The ECP/HOP mixture (named ECHOPvir) was characterized for the antioxidant and cytoprotective properties in airway cells. Moreover, the immunomodulating properties of the mixture in murine macrophages against antioxidant and inflammatory stimuli and its antiviral efficacy against the PR8/H1N1 influenza virus were assayed. The modulation of the Nrf2 was also investigated as a mechanistic hypothesis. The ECP/HOP mixture showed a promising multitarget bioactivity profile, with combined cytoprotective, antioxidant, immunomodulating and antiviral activities, likely due to the peculiar phytocomplexes of both ECP and HOP, and often potentiated the effect of the single extracts. The Nrf2 activation seemed to trigger these cytoprotective properties and suggest a possible usefulness in counteracting the damage caused by different stressors, including viral infection. Further studies may strengthen the interest in this product and underpin its future nutraceutical applications.

Umbelliferone and eriodictyol suppress the cellular entry of SARS-CoV-2

BACKGROUND

Artemisia argyi (A. argyi), also called Chinese mugwort, has been widely used to control pandemic diseases for thousands of years since ancient China due to its anti-microbial infection, anti-allergy, and anti-inflammation activities. Therefore, the potential of A. argyi and its constituents in reducing the infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was investigated in this study.

RESULTS

Among the phytochemicals in A. argyi, eriodictyol and umbelliferone were identified to target transmembrane serine protease 2 (TMPRSS2) and angiotensin-converting enzyme 2 (ACE2) proteins, the essential factors for the cellular entry of SARS-CoV-2, in both FRET-based enzymatic assays and molecular docking analyses. These two ingredients of A. argyi suppressed the infection of ACE2-expressed HEK-293 T cells with lentiviral-based pseudo-particles (Vpp) expressing wild-type and variants of SARS-CoV-2 spike (S) protein (SARS-CoV-2 S-Vpp) via interrupting the interaction between S protein and cellular receptor ACE2 and reducing the expressions of ACE2 and TMPRSS2. Oral administration with umbelliferone efficiently prevented the SARS-CoV-2 S-Vpp-induced inflammation in the lung tissues of BALB/c mice.

CONCLUSIONS

Eriodictyol and umbelliferone, the phytochemicals of Artemisia argyi, potentially suppress the cellular entry of SARS-CoV-2 by preventing the protein binding activity of the S protein to ACE2.